Is it real? What does it hold for the future? http://www.allvoices.com/contribute...reate-antimatter-a-breakthrough-in-antimatter http://www.pcmag.com/article2/0,2817,2372994,00.asp
Fermilab has been making antiprotons for decades. They collide protons with antiprotons in their collider. They store large quantities of antiprotons before injecting it into their ring. This is not new, and is bogus hype. Apparently the only 'new' thing about it is that the antiprotons are allowed to obtain positrons in orbit, forming non-ionized anti-hydrogen, whereas Fermilab makes only ionized anti-Hydrogen (i.e. bare antiprotons) which is easier to store in a magnetic bottle.
Having anti-matter atomic systems will allow you to do spectroscopy of the anti-hydrogen atoms which is a sensitive test of the predictions of quantum field theory. An exact symmetry between matter and anti-matter could be tested at a very high level of precision. And if asymmetry could be measured, that would impact theoretical results. As anti-hydrogen is neutral, it might be easier to test the gravitational equivalence principle with a few atoms of anti-hydrogen than with just millions of anti-protons.
It's certainly not "bogus hype." Individual anti particles have been made at colliders pretty much since the start of colliders, and anti-electrons, or positrons, occur in nature as a result of beta plus decays, but actual anti elements have never been trapped for a reasonable amount to time before. Making anti hydrogen, as rpenner said, is important because you can do precision tests on it and see whether charge conjugation and parity really are symmetries of nature. Trapping antihydrogen is hard for 2 reasons. Firstly, anti protons are made in colliders and as such are moving very fast. You have to find a way to slow them down without coming into contact with any normal matter otherwise they disappear in a burst of energy. Secondly antihydrogen is electrically neutral. For antiparticles that are electrically charged you can hold them in what's called a Penning trap which uses a combination of electric and magnetic fields to hold the particles in one place in vacuum (despite what Walter thinks). Since antihydrogen has no net charge, but it does have a magnetic moment because of the spins of it's constituents, you can only use magnetic fields to hold them. That's actually a very hard problem because the magnetic potential obeys the Laplace equation so, As I'm sure Walter knows very well, if you have a field that has a minimum in the x and y directions, there will be a maximum at the same point in the z direction and the particles will fly off. That means you have to use a variable magnetic field. I actually did a project in my undergrad degree into trapping macroscopic charged particles in a variable electric field that's kind of similar to this in that you have to use an alternating electric field. This is called a Paul trap. Of course, this is really a very easy problem for Walter because I'm sure if he tried to trap antihydrogen he's be able to do it 50% of the time.
Antiprotons are not made in colliders. They are made in fixed-target particle accelerators. Fermilab has 'captured' them by the millions, and stored them for hours, because they are in a storage ring for their proton/antiproton collisions for hours. This is a new type of 'magnetic bottle' allowing only a few atoms to be collected at a time. I believe they are actually ionized as well, so they are not even ground-state atoms with positrons, but ionized atoms (i.e. no positrons in orbit). It is 'hype' by the newsmedia, when this is quite ho-hum for Fermilab. Unless someone from Fermilab wants to correct me on this, and say how excited they are by this.
What happens when ordinary matter goes into an antimatter black hole? There must be a lot of them when you think about it?
"To create antihydrogen and keep it from immediately annihilating, the ALPHA team cooled antiprotons and compressed them into a matchstick-size cloud. Then the researchers nudged this cloud of cold, compressed antiprotons so it overlapped with a like-size positron cloud, where the two particles mated to form antihydrogen. All this happened inside a magnetic bottle that traps the antihydrogen atoms. The magnetic trap is a specially configured magnetic field that uses an unusual and expensive superconducting magnet to prevent the antimatter particles from running into the edges of the bottle - which is made of normal matter and would annihilate with the antimatter on contact. 'For the moment, we keep antihydrogen atoms around for at least 172 milliseconds - about a sixth of a second - long enough to make sure we have trapped them,' said Jonathan Wurtele, a University of California, Berkeley professor of physics and LBNL faculty scientist." It appears that they mate the antiprotons with antielectrons.
Petty, narcissistic, pedantic bullcrap -- like when Wagner took a red pen to the work of Nobel Laureates and submitted that to the Court. The first antiprotons to be created by man were at the fixed target Bevatron at 6 GeV in 1955. Using a fixed target means that the created particles have an average momentum in the direction of the initial beam, which is useful for collecting the particles and sorting them by mass, momentum and charge via magnetic fields and apertures. According to Fermilab, they do much the same, in a vital annex to what ultimately is a proton-antiproton collider. They just don't make the antiprotons for the fun. http://www-bd.fnal.gov/public/antiproton.html#target But to the theorist, the type of the apparatus (fixed target or one where beams in opposite directions collide) is irrelevant to the physics of the particle collisions. Specifically, antiprotons are created in scads at all of these physics machines where the center-of-mass energy is high enough or higher. More massive anti-baryons decay to antiprotons, which is the longest-lived and lowest mass anti-baryon. Which is why picking on the choice of word is pedantic bullcrap. Not only are antiprotons created at some collider complexes for the purposed of being used as source material, but antiprotons are generically produced in collisions. It's CERN actually. http://scienceblogs.com/principles/2010/11/trapped_antihydrogen.php http://press.web.cern.ch/press/PressReleases/Releases2010/PR22.10E.html http://alpha.web.cern.ch/alpha/ And Nature seems pretty excited: http://www.nature.com/news/2010/101117/full/468355a.html
How petty. Fermilab does NOT make their antiprotons in the collider. They are made elsewhere and used in (i.e injected into) the collider, NOT made in the collider. There is nothing wrong about correcting Prometheus or any other person who misstates the facts.
Yes, lots of things are made in the collisions in the colliders, including some antiprotons. But those are not the source of the antiprotons referenced in the article. Prometheus (and you) are leaving the impression with the reader that the collider produces the antiprotons, which are then trapped in a bottle for study. That is not true. The antiprotons referenced are not made in the LHC collider ring, but elsewhere at CERN. That's why your comments about me actually relate to yourself quite nicely.
They are made in a collider which is connected to the main collider. Often the initial particle generator is just an old collider which has been kept in order to use it to make the particles to go into the newer collider. As Rpenner says, the physics is identical (due to Lorentz boosting), the construction is much the same and they are all connected to one another, making one giant machine. Just because we don't use the 10GeV section as the primary collider doesn't mean its not a collider, it just has a slightly different purpose. Your attempt at splitting of hairs is like saying "Fuel injectors aren't part of a car engine because they aren't the parts which burn the fuel". And Prom didn't say they used a Penning trap for the antiprotons, he was commenting on why antihydrogen is difficult to work with, it can't be manipulated via magnetic fields, which is a common way of capturing charged particles.
No, they are made in a fixed-target accelerator that is connected to the collider accelerator (aka LHC). The term collider has a very specific meaning - two beams running in opposite directions are made to collide into each other. Fixed-target accelerators have a single beam that then strikes a fixed target. That is where the antiprotons are made, when a proton beam strikes a fixed target. This does not happen in the LHC collider (though as mentioned, some incidental antiprotons are made there, but not used for anything).
While the LHC is, formally, the main set of rings, with the detectors, injectors, storage rings etc being separate people will refer to the entire setup as 'the LHC'. In that regard the statement "The LHC generates, stores and then uses antiprotons" would be perfectly valid. Fixed targets still require collisions to produce their outputs and since the ones at places like Fermilab and the LHC are directly connected into the main accelerating section its not even necessary to draw a distinction between what are basically subcomponents of a single device. You'll find the terminology is used interchangeably within the research community. But that's because everyone in the community knows the specifics of what each part of things like the LHC does and the physics behind it. They (or rather, we) aren't so insecure in their understanding that someone would put up their hand in the middle of a talk on Drell-Yan processes in Higgs production at the LHC to whine about the difference between an accelerator and a collider. Its like when mathematicians abuse notation, the only people who complain are those who don't really understand but want to be seen to be familiar with the subject. Besides, I think you should be spending your time a little more wisely Walter. Perhaps you should spend less time telling particle physicists about their abuse of terminology and a little more time trying to understand the physics at hand? After all, whether you call them the same thing or not, the underlying physics models are precisely the same so physicists could call them whatever the hell they like, rightly or wrongly, provided their quantitative predictions are accurate. But I guess that's the side of physics you're not very familiar with Please Register or Log in to view the hidden image!
Guess I didn't know we'd have controversy over this topic. Please Register or Log in to view the hidden image! I do appreciate all the discussion. I'm learning things. Please Register or Log in to view the hidden image!
Perhaps so, but to the average reader of this forum (who for the most part are not part of the CERN physics community), the distinction between a fixed-target accelerator (in which a moving beam crashes into, or collides with a non-moving target) and a collider (in which there are two moving beams that are made to collider with each other) is a substantial difference, so they are not left in confusion.
Not really. I'm no nuclear physicist, but I can certainly tell when you are making a mountain out of a molehill due to some burr under your saddle.
To the "average reader" there is very little difference (or none at all) between a fixed-target accelerator and a collider. When it comes down to it they're both (just) phenomenally expensive pieces of gee-whizzery. Any "distinction" for the "average reader" is as a much a distinction between one baked bean and another from the same tin.
